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Venous thromboembolism is a leading cause of morbidity and mortality in patients with active cancer who require anticoagulation treatment. Choice of anticoagulant is based on careful balancing of the risks and benefits of available classes of treatment: vitamin K antagonists, low-molecular-weight heparin (LMWH), and direct oral anticoagulants (DOACs). Results from randomized controlled trials have shown the consistent efficacy of DOACs versus LMWH in the treatment of cancer-associated venous thromboembolism (VTE). However, increased major gastrointestinal bleeding was observed for edoxaban and rivaroxaban, but not apixaban, compared with LMWH dalteparin. Most guidelines recommend DOACs for the treatment of cancer-associated VTE in patients without gastrointestinal or genitourinary cancer, and with considerations for renal impairment and drug–drug interactions. These updates represent a major paradigm shift for clinicians in the Middle East and North Africa. The decision to prescribe a DOAC for a patient with cancer is not always straightforward, particularly in challenging subgroups of patients with an increased risk of bleeding. In patients with gastrointestinal malignancies who are at high risk of major gastrointestinal bleeds, apixaban may be the preferred DOAC; however, caution should be exercised if patients have upper or unresected lower gastrointestinal tumors. In patients with gastrointestinal malignancies and upper or unresected lower gastrointestinal tumors, LMWH may be preferred. Vitamin K antagonists should be used only when DOACs and LMWH are unavailable or unsuitable. In this review, we discuss the overall evidence for DOACs in the treatment of cancer-associated VTE and provide treatment suggestions for challenging subgroups of patients with cancer associated VTE. Plain Language Summary: Patients with cancer are at risk of blood clots forming in their veins, which can cause illness and death. To prevent such blood clots, most patients with cancer need anticoagulant therapy. There are three types of anticoagulants available for the treatment of cancer-associated blood clots in a vein, namely, vitamin K antagonists, low-molecular-weight heparin (LMWH), and direct oral anticoagulants (DOACs). Drug trials have shown that DOACs are more effective than LMWH; however, DOACs can have a greater risk of causing major gastrointestinal bleeding. Among DOACs, edoxaban and rivaroxaban are drugs associated with higher rates of gastrointestinal bleeding. Recently updated guidelines for doctors recommend that DOACs be used as the first treatment for patients with cancer at risk of blood clot formation in a vein. For doctors in the Middle East and North Africa, this new approach differs from existing practices. Notably, choosing a treatment also depends on the type of cancer, because gastrointestinal cancers and cancers of the genitals and urinary system have an especially high risk of gastrointestinal bleeding. The choice also depends on the presence of kidney problems, drug–drug interactions, and access to the drugs. Apixaban may be the preferred DOAC in patients with gastrointestinal cancer, but this drug should be used with care in patients with upper or unresected lower gastrointestinal tumors. For patients with upper or unresected lower gastrointestinal tumors, treatment with LMWH may be preferred. Vitamin K antagonists should be used only when DOACs and LMWH are unavailable or unsuitable. [ABSTRACT FROM AUTHOR]

Background: Direct oral anticoagulants (DOACs) used as an alternative to low-molecular-weight heparin (LMWH) for thromboprophylaxis after cancer surgery for venous thromboembolic events (VTE) remains unclear. This study aimed to investigate the efficacy and safety of DOACs versus LMWH in these patients. Materials and methods: A search of EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science was carried out and included all randomized controlled trials (RCTs) and observational studies that directly compared DOACs with LMWH for thromboprophylaxis in patients after cancer surgery through July 25, 2023. The primary efficacy and safety outcomes were VTE, major bleeding, and clinically relevant non-major bleeding (CRNMB) within 30 days of surgery. The risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB2) tool for RCTs and ROBINS-I tool for non-randomized studies. This study was registered in PROSPERO (CRD42023445386). Results: We retrieved 5149articles, selected 27 for eligibility, and included 10 studies (three RCTs and seven observational studies) encompassing 3054 patients who underwent postoperative thromboprophylaxis with DOACs (41%) or LMWH (59%). Compared to LMWH thromboprophylaxis, DOACs had a comparable risk of VTE (RR:0.69[95% CI:0.46–1.02], I2 = 0%), major bleeding (RR:1.55 [95% CI:0.82–2.93], I2 = 2%), and CRNMB (RR, 0.89 [95% CI, 0.4–1.98], I2 = 31%) during the 30-day postoperative period. Subgroup analysis of VTE and major bleeding suggested no differences according to study type, extended thromboprophylaxis, tumor types, or different types of DOAC. Conclusion: DOACs are potentially effective alternatives to LMWH for thromboprophylaxis in patients undergoing cancer surgery, without increasing the risk of major bleeding events. [ABSTRACT FROM AUTHOR]

Source Citation: Schrag D, Uno H, Rosovsky R, et al; CANVAS Investigators. Direct oral anticoagulants vs low-molecular-weight heparin and recurrent VTE in patients with cancer: a randomized clinical trial. JAMA. 2023;329:1924-1933. 37266947 Clinical Impact Ratings: GIM/FP/GP: Hospitalists: Oncology: Hematology: [ABSTRACT FROM AUTHOR]

Key Points: Question: Among patients with cancer and a venous thromboembolism (VTE) event, are direct oral anticoagulants noninferior to low-molecular-weight heparin for preventing recurrent VTE events? Findings: In this pragmatic, noninferiority randomized clinical trial that included 638 patients from 67 centers with cancer and a new VTE, direct oral anticoagulants, compared with low-molecular-weight heparin, resulted in a recurrent VTE rate of 6.1% vs 8.8% at 6 months. The upper confidence limit around the difference was less than the noninferiority margin of 3%. Meaning: Among adults with cancer and VTE, direct oral anticoagulants were noninferior to low-molecular-weight heparin for preventing recurrent VTE over 6-month follow-up. Importance: In patients with cancer who have venous thromboembolism (VTE) events, long-term anticoagulation with low-molecular-weight heparin (LMWH) is recommended to prevent recurrent VTE. The effectiveness of a direct oral anticoagulant (DOAC) compared with LMWH for preventing recurrent VTE in patients with cancer is uncertain. Objective: To evaluate DOACs, compared with LMWH, for preventing recurrent VTE and for rates of bleeding in patients with cancer following an initial VTE event. Design, Setting, and Participants: Unblinded, comparative effectiveness, noninferiority randomized clinical trial conducted at 67 oncology practices in the US that enrolled 671 patients with cancer (any invasive solid tumor, lymphoma, multiple myeloma, or chronic lymphocytic leukemia) who had a new clinical or radiological diagnosis of VTE. Enrollment occurred from December 2016 to April 2020. Final follow-up was in November 2020. Intervention: Participants were randomized in a 1:1 ratio to either a DOAC (n = 335) or LMWH (n = 336) and were followed up for 6 months or until death. Physicians and patients selected any DOAC or any LMWH (or fondaparinux) and physicians selected drug doses. Main Outcomes and Measures: The primary outcome was the recurrent VTE rate at 6 months. Noninferiority of anticoagulation with a DOAC vs LMWH was defined by the upper limit of the 1-sided 95% CI for the difference of a DOAC relative to LMWH of less than 3% in the randomized cohort that received at least 1 dose of assigned treatment. The 6 prespecified secondary outcomes included major bleeding, which was assessed using a 2.5% noninferiority margin. Results: Between December 2016 and April 2020, 671 participants were randomized and 638 (95%) completed the trial (median age, 64 years; 353 women [55%]). Among those randomized to a DOAC, 330 received at least 1 dose. Among those randomized to LMWH, 308 received at least 1 dose. Rates of recurrent VTE were 6.1% in the DOAC group and 8.8% in the LMWH group (difference, −2.7%; 1-sided 95% CI, −100% to 0.7%) consistent with the prespecified noninferiority criterion. Of 6 prespecified secondary outcomes, none were statistically significant. Major bleeding occurred in 5.2% of participants in the DOAC group and 5.6% in the LMWH group (difference, −0.4%; 1-sided 95% CI, –100% to 2.5%) and did not meet the noninferiority criterion. Severe adverse events occurred in 33.8% of participants in the DOAC group and 35.1% in the LMWH group. The most common serious adverse events were anemia and death. Conclusions and Relevance: Among adults with cancer and VTE, DOACs were noninferior to LMWH for preventing recurrent VTE over 6-month follow-up. These findings support use of a DOAC to prevent recurrent VTE in patients with cancer. Trial Registration: ClinicalTrials.gov Identifier: NCT02744092 This randomized trial assesses the comparative effectiveness of direct oral anticoagulants vs low-molecular-weight heparin on rate of 6-month recurrence of venous thromboembolism (VTE) among patients with cancer who had a new diagnosis of VTE. [ABSTRACT FROM AUTHOR]

Cancer is a major risk factor for venous thromboembolism (VTE), and cancer-associated thrombosis (CAT) constitutes approximately 15– 25% of all VTE cases. For decades, the standard treatment for CAT used to be daily subcutaneous low molecular weight heparin (LMWH). Data on the safety and efficacy of the direct oral anticoagulants (DOACs) in this population emerged only in recent years and specific DOACs were included into recent guidelines recommendations. In this narrative review of the literature, we reported the results of the phase III randomized controlled trials that evaluated the DOACs for the prevention and the acute treatment of CAT. For the acute phase treatment, the anti-Xa inhibitors (apixaban, edoxaban, rivaroxaban) showed better efficacy than LMWH in preventing VTE recurrence; however, rivaroxaban and edoxaban were also associated with an increased risk of bleeding events. For primary prevention of CAT in ambulatory cancer patients starting chemotherapy, apixaban and rivaroxaban showed better efficacy than placebo but a trend towards higher bleeding rates. Recent guidelines suggest the DOACs for the treatment of CAT in selected cancer patients (eg, low bleeding risk, no luminal gastrointestinal or genitourinary malignancies, no interfering medications). The DOACs are also suggested for primary thromboprophylaxis in selected ambulatory cancer patients at high risk of VTE (eg, Khorana score ≥ 2 prior to starting new chemotherapy, low bleeding risk, no interfering medications). [ABSTRACT FROM AUTHOR]

Summary: Cancer‐associated venous thromboembolism (VTE) is a leading cause of morbidity and mortality in patients with cancer. Treatment of cancer‐associated VTE comes with a heightened risk of anticoagulant‐related bleeding that differs by choice of anticoagulant as well as by patient‐ and disease‐specific risk factors. Available data from randomized controlled trials and observational studies in cancer‐associated VTE suggest that direct oral anticoagulants are effective, continuing anticoagulation beyond six months is indicated in those with active cancer and that patients who develop 'breakthrough' thrombotic events can be effectively treated. We review the evidence that addresses these key clinical questions and offer pragmatic approaches in individualizing care. While significant investigative efforts over the past decade have made impactful advances, future research is needed to better define the factors that contribute to anticoagulant‐related bleeding and VTE recurrence, in order to aid clinical decision‐making that improves the care of patients with cancer‐associated VTE. [ABSTRACT FROM AUTHOR]

Cancer-associated venous thromboembolism is a devastating complication of cancer and is associated with significant morbidity and mortality. The cornerstone of cancer-associated venous thromboembolism treatment is anticoagulation, and in recent years, there have been notable randomized clinical trials that have revealed insights into the efficacy and safety of direct oral anticoagulants and low-molecular-weight heparin in the treatment of cancer-associated thrombosis. Deciding on the ideal anticoagulation treatment plan for a patient with a cancer-associated thrombosis is a complex task that requires an understanding of clinical trial data, society guidelines, and, most importantly, consideration of many cancer-related, treatment-related, and patient-related factors. This article summarizes important factors to consider when deciding on anticoagulation therapy for a patient with cancer-associated thrombosis. [ABSTRACT FROM AUTHOR]

The Ottawa score (OS) for predicting the risk of recurrent venous thromboembolism (VTE) in cancer patients with VTE may help to guide anticoagulant treatment decisions that will optimize benefit-risk ratios. However, data on its reliability are conflicting. We applied the OS to all cancer patients with VTE enrolled in the prospective multicenter TROPIQUE study who received low-molecular-weight heparin over a 6-month period. Of 409 patients, 171 (41.8%) had a high-risk OS. The 6-month cumulative incidence of recurrent VTE was 7.8% (95%CI 4.2–14.8) in the high-risk OS group versus 4.8% (95%CI 2.6–8.9) in the low-risk OS group (SHR 1.47; 95%CI 0.24–8.55). The Area Under the Receiver Operating Characteristic curve (AUROC) of the OS in identifying patients who developed recurrent VTE was 0.53 (95%CI 0.38–0.65), and its accuracy was 57.9%. Among individual variables included in the OS, only prior VTE was significantly associated with the 6-month risk of recurrent VTE (SHR 4.39; 95% CI 1.13–17.04). When pooling data from all studies evaluating this score for predicting VTE recurrence in cancer patients (7 studies, 3413 patients), the OS estimated pooled AUROC was 0.59 (95%CI 0.56–0.62), and its accuracy was 55.7%. The present findings do not support the use of the OS to assess the risk of recurrent VTE in cancer patients. [ABSTRACT FROM AUTHOR]

International clinical practice guidelines have progressively endorsed direct oral anticoagulants (DOACs) as an alternative to low-molecular-weight heparins (LMWHs) monotherapy for the initial and long-term treatment of cancer-associated thrombosis (CAT). Several new randomized controlled trials (RCTs) have recently reported additional results on the safety and efficacy of DOACs in this setting. We performed an updated meta-analysis of all publicly available data from RCTs comparing DOACs with LMWHs for the treatment of CAT. Six RCTs enrolling 3690 patients with CAT were included. Compared with LMWHs, DOACs significantly decreased the risk of CAT recurrence (RR, 0.67; 95%CI, 0.52–0.85), with a non-significant increase in the risk of major bleeding (RR, 1.17; 95%CI, 0.82–1.67), a significant increase in the risk of clinically relevant nonmajor bleeding (RR 1.66; 95%CI, 1.31–2.09) and no difference in all-cause mortality rates. These results increase the level of certainty of available evidence supporting the use of DOACs as an effective and safe option for the treatment of CAT in selected cancer patients. [ABSTRACT FROM AUTHOR]